Very hard materials such as glass, stone, tile, ceramic and porcelain, generally cannot be drilled with standard steel or carbide bits because of the extreme hardness of the material. One solution is to bond diamonds (or other extremely hard materials) onto the tip of a specially designed drill bit, allowing the diamonds to perform the actual cutting process. Diamonds are extremely hard and provide a durable cutting edge.
Several drawbacks are attendant to the use of diamonds on drill bits. The more diamonds that are bonded to the cutting edge, the longer the life of the bit. However, additional diamond layers have less bond strength and result in a thicker cut in the work piece. In addition, during use, two primary forces act upon the diamond cutting edge and the bond: 1) the physical force of the cutting action, and 2) heat caused by friction. Because of the hardness of diamonds, the most limiting factor in diamond drill bit life is generally the destruction of the bond structure that holds the diamonds onto the drill bit tip. The diamonds don't normally wear out; they break off or fall off as the drilling forces and heat overcome the bond.
It is an object of the invention to provide a means to extend the life of the drill bit by increasing the quantity of diamonds on the cutting edge while minimizing their thickness. It is further an object of the present invention to maximize the bond strength while minimizing the shear forces acting on bonds holding the diamonds to the sidewalls of the drill bit. And, it is further an object of the present invention to reduce the heat generated by friction of the cutting action.
The present invention incorporates a unique combination of features that provide optimal drilling efficiency in both natural and man made materials. The invention incorporates simple and efficient means for (1) minimizing waste in the cut material with an overall bit design that enables the use of a thin-walled drill bit; (2) improving diamond quantity and bond strength on the bit's cutting edge to lengthen the life of the bit; (3) lubricating the cutting surface from the inside of the bit using center lubricant feed system to improve the cut; (4) removing cutting debris from the inside of the bit to reduce cutting time and heat generation; (5) obtaining a smooth bore in the drilled material to improve quality; and (6) removing the core from the drill bit when the cut is finished to reduce time to completion.